sql server - Why would this table allow a PK id of 0? -

in sql server 2008 r2, have table allows 0 foreign key. odd because primary key constraint specified, , identity(1,1) descriptor used.

when first record inserted table, it's pk (regionid) 0.

i don't have identity-insert turned on when doing insert. (normal operation)

here's table definition:

create table [dbo].[tdfregions](     [regionid] [int] identity(1,1) not null,     [regionname] [nvarchar](50) not null,     [regiondescription] [nvarchar](50) not null,     [active] [bit] not null,  constraint [pk_tdfregions] primary key clustered  (     [regionid] asc )with (pad_index  = off, statistics_norecompute  = off, ignore_dup_key = off, allow_row_locks  = on, allow_page_locks  = on) on [primary] ) on [primary]  go  

i have been acting under assumption first record inserted table have regionid of 1.

insert      tdfregions (regionname, regiondescription, active)  values      ('test','test', 1) 

produces:

regionid   regionname   regiondescription   active     0      test         test                   1 

why might happening?

edit:

ok, i've got little more background information here. ran

exec sp_msforeachtable 'alter table ? nocheck constraint all' go exec sp_msforeachtable 'delete ?' go exec sp_msforeachtable 'alter table ? check constraint all' go 

to clear database when first created. have been responsible?

the reason end 0 in regionid --

when truncate table , reseed identity 0 using below command

dbcc checkident('tdfregions', reseed, 0) 

if insert table insert block, regionid = 0.